The present invention is directed to a method of detecting a leak in an outer jacket of a metal halide lamp and a lamp and ballast that carry out the method.
Metal halide lamps include an arc tube inside an outer jacket and are operated by a ballast. One of the problems associated with such metal halide lamps is that the outer jacket can leak without causing failure of the arc tube. A leak in the outer jacket degrades lamp operation or causes the lamp to fail and a serious leak can lead to a more dangerous situation, such as UV exposure, electrical shock, and/or hot projectiles. It is desirable to detect these leaks to be able to take corrective action.
In new metal halide lamps, the traditional magnetic ballasts are being replaced with newer electronic ballasts that have increased functionality. For example, the electronic ballast may include a processor and/or other electronic components that can be programmed or otherwise arranged to perform various functions related to lamp operation. See, for example, the electronic ballasts in U.S. Pat. Nos. 7,002,305 and 7,129,647.